Sounds like a very useful feature to me, and something that competitors or previous products did not had.
And "deciding how something should work" sounds like a perfectly good description of an _invention_.
How you came to the conclusion that "If the implementation is too hard, the idea was worthless", I can't even begin to think.
Difficulty of implementation and worthiness of idea are totally orthogonal.
There are tons of very important ideas that had a very difficult implementation. E.g the idea behind the atomic bomb was very valuable despite the fact that the implementation took some of the top minds, several years and millions of dollars.
If you take only one patent as an example, maybe not. But if Apple couldn't secure ANY patent on the iPhone, and any competitor was free to copy it as he liked, well, not only the might have not produced it, but the very industry might not even exist and have the scope it has today.
The iPhone is a very successful product, and it owes very little of that success to patents.
It's true that when some areas offer artificial monopolies and others don't, investors like the former. But extending the domain of monopolies isn't the only way to debias that.
Apple makes the Mac Pro, the iMac, Macbook Pro, Macbook Air, which are all generic computers, which anyone can (and does) copy. Do you think they would not do it since they can't patent a laptop computer, that's rectangular? Or an all-in-one computer? Or a tower computer?